A dye-sensitized solar cell is developed by Gratzel, et al., (Swiss), has advantages of high photoelectric conversion efficiency and low manufacturing cost, and attracts attention as a new type solar cell.
The dye-sensitized solar cell has a structure in which a working electrode on which a porous oxide semiconductor layer having a photo-sensitized dye supported thereon and a counter electrode that is provided so as to face the working electrode are provided on a transparent base having a transparent semiconductor film provided thereon, in which an electrolyte containing redox pairs is filled between the working electrode and the counter electrode and sealed by a sealing member.
In this type of dye-sensitized solar cell, when the photo-sensitized dye absorbs incident light, such as sun light or the like, electrons are generated and injected into oxide semiconductor fine particles, and electromotive force is generated between the working electrode and the counter electrode. In this way, the dye-sensitized solar cell serves as a photoelectric conversion element that converts light energy into power.
In general, as the electrolyte, an electrolytic solution obtained by dissolving redox pairs, such as I−/I3−, in an organic solvent, such as acetonitrile, is used. In addition, for example, the following structures have been known: a structure using a non-volatile ionic liquid; a structure that gelates a liquid electrolyte with an appropriate gelling agent to pseudo-solidify the liquid electrolyte; and a structure using a solid-state semiconductor, such as a p-type semiconductor.
The counter electrode needs to be made of a material having resistance to corrosion that is caused by a chemical reaction with the electrolyte. As the material, a titanium substrate on which a platinum film is formed or a glass electrode substrate on which a platinum film is formed may be used.
A dye-sensitized solar cell has been suggested in which evaporation of a volatile solvent contained in the electrolytic solution can be prevented by sealing performed by heating and melting Himilan (trade name, produced by Du Pont-Mitsui Polychemicals Co., Ltd.), which is generally an ionomer (see, for example, Patent Document 1).
A dye-sensitized solar cell has also been suggested in which evaporation of a volatile solvent contained in the electrolytic solution can be prevented by sealing performed by heating and melting an ethylene—vinyl alcohol copolymer since such copolymer has gas barrier ability superior to that of Himilan (see, for example, Patent Document 2).    Patent Document 1: Japanese Patent Application Publication No. 2003-297446    Patent Document 2: Japanese Patent Application Publication No. 2007-149652